An Inconvenient Truth: The Unconsidered Benefits of Convenience Polyandry

Abstract

In the last two decades molecular techniques have revealed that polyandry, or multiple mating by females with different males, is common. One explanation is that females engage in convenience polyandry, mating multiply to reduce the costs of sexual harassment. Although the underlying logic of convenience polyandry is clear, and harassment often seems to influence mating outcomes, it has not been subjected to as thorough theoretical or empirical attention as other explanations for polyandry. Here, we reexamine convenience polyandry in the light of a new generation of studies showing previously unconsidered benefits of polyandry. We suggest that true convenience polyandry is likely to be a fleeting phenomenon, but a phenomenon that can profoundly shape mating system evolution due to potential feedback loops between resistance to males and the costs and benefits of mating. The history of polyandry Mating systems are often classified as either monogamous, with a single male paired with a single female, or polygamous, with multiple mates of one or the other sex. Polygamy in turn can be subdivided into polygyny (one male with multiple females) or polyandry (one female with multiple males; see glossary). The near ubiquitous nature of polygyny has never been debated, but polyandry has had a somewhat contradictory history. On the one hand, researchers using insects and other invertebrates as study organisms have often acknowledged the prevalence of

An inconvenient tooth: Evaluating female choice in multiple paternity using an evolutionarily and ecologically important vertebrate clade

“…Our study provides a comprehensive analysis and novel approach for considering the drivers of multiple paternity in elasmobranchs. While it is becoming clear that polyandry is more the rule than the exception (Lamarca et al, 2020), the exact mechanisms behind this phenomenon have received little attention beyond the notion of convenience polyandry, which is difficult to empirically demonstrate (Boulton et al, 2018) and has not been formally tested in elasmobranchs. While we do not discount male‐based drivers as playing an important role in the reproductive process, we caution against these being used as the only explanations for the high occurrence of polyandry across elasmobranch mating systems in the absence of empirical testing.…”

“…We dedicate this manuscript to the notorious R.B.G., a champion of female choice. We tip our hat to Boulton et al (2018) for laying out the inconveniences surrounding convenience polyandry to which our manuscript title pays homage. We thank L. Natanson at the Northeast Fisheries Science Center for access to historical records detailing litter and reproductive morphometrics in sampled species.…”

“…Explanations of this phenomenon are most often casually attributed to “convenience polyandry,” where females are presumed to mate with multiple males simply because the cost of avoiding rigorous copulatory behaviour is too high (e.gBarker et al, 2019; DiBattista et al, 2008; DiBattista et al, 2008; Feldheim et al, 2004; Griffiths et al, 2011; Lage et al, 2008; Nosal et al, 2013; Pirog et al, 2017; Rossouw et al, 2016). However, empirically demonstrating convenience polyandry as the main driver of multiple paternity is quite difficult (Boulton et al, 2018), and many studies lack the power to make broad conclusions about the mating system in the first place due to low sample sizes or the opportunistic nature of their sampling schemes. Furthermore, the generally low genetic diversity of microsatellite markers, or few numbers of markers used, in elasmobranch studies along with small litter sizes in some species makes demonstrating a lack of multiple paternity even more difficult.…”

Genetic benefits of extreme sequential polyandry in a terrestrial‐breeding frog

“…; Boulton et al. ). However, in cases where females actively solicit copulations with multiple males we can assume that polyandry is an adaptive female mating strategy (Byrne and Roberts ).…”

“…Therefore, unnecessary matings should be strongly selected against. In some species, females may be coerced into mating by promiscuous males and accept additional matings to reduce the costs of sexual harassment (Rice et al 2006;Boulton et al 2018). However, in cases where females actively solicit copulations with multiple males we can assume that polyandry is an adaptive female mating strategy (Byrne and Roberts 2012).…”